Semiconductor light emitting devices such as Light Emitting Diodes (LED) or laser diodes are widely used for many applications. As is well known to those having skill in the art, a semiconductor light emitting diode is generally packaged by at least partially surrounding the semiconductor light emitting diode with a dome-shaped transparent plastic shell.
It is often desirable to incorporate a phosphor into the light emitting device, to enhance the emitted radiation in a particular frequency band and/or to convert at least some of the radiation to another frequency band. Phosphors may be included in a light emitting device using many conventional techniques. In one technique, phosphor is coated inside and/or outside the plastic shell. In other techniques, phosphor is coated on the semiconductor light emitting device itself, for example using electrophoretic deposition. In still other embodiments, a drop of a material such as epoxy that contains phosphor therein may be placed inside the plastic shell, on the semiconductor light emitting device and/or between the device and the shell. LEDs that employ phosphor coatings are described, for example, in U.S. Pat. Nos., 6,252,254; 6,069,440; 5,858,278; 5,813,753; 5,277,840; and 5,959,316.
Packaging may constitute a major portion of the expense and/or fabrication time for a finished light emitting device.